This invention relates to a tape cassette, and more particularly to a tape cassette which is provided with a liner sheet intended to prevent a magnetic tape from being irregularly wound about a hub.
When a magnetic tape received in an audio apparatus is made to run at the time of recording, reproduction or rewind, the tape is generally wound about one of the two hubs. In this case, the hub tends to be shaken while being wound with a tape, sometimes resulting in the irregular winding of the tape. To prevent the occurrence of such an objectionable event, therefore, a liner sheet is held between the tape and half case to prevent the shaking of the hub.
A presently known liner sheet includes not only a flat type but also a type having a purposely modulated surface. In the case of either of the conventional liner sheets, suppressing the shaking of the hub has been tried by simply causing the liner sheet to contact the edge of a magnetic tape wound about the hub. However, the hub is noticeably shaken particularly at the initial stage of tape winding. The reason for this occurrence is that when initially wound about the hub, the tape has a particularly small radius of curvature and high tension on the tape. Consequently any increased rigidity of the magnetic tape or any irregular winding of the tape about the hub causes the hub to be significantly affected by the resultant tension of such an irregular tape. The tension of the tape exerts a noticeable action on the hub not only in its rotating direction but also in a direction perpendicularly to the rotating direction. Moreover at the initial stage of tape winding, a minimum amount of mass is present at the hub which, consequently, is held in an unstable state and is more readily shaken.
When a tape is wound about the hub, it sometimes happens that a linearly travelling tape to be wound about a hub has its edge displaced from a prescribed position on the hub, or the edge of the succeeding portion of the travelling tape is displaced from the edge of the preceding portion of the tape which has already been wound about the hub. With the conventional tape cassette, therefore, a tape sometimes tends to be irregularly wound about the hub, presenting difficulties in ensuring the stable run of the tape.